Ordering Recommendation

Provides a calculated value for free testosterone concentration using total testosterone measured by immunoassay. Use to evaluate hypogonadism in cisgender males with a total testosterone concentration at the lower limit of normal. May be used to evaluate testosterone status in individuals with protein-binding abnormalities or to monitor testosterone hormone therapies. Not recommended when low testosterone concentrations, such as those found in children and cisgender females, are expected. For these individuals, testing by mass spectrometry is recommended; refer to Testosterone, Free and Total, Includes Sex Hormone-Binding Globulin (Adult Females, Children, or Individuals on Testosterone-Suppressing Hormone Therapy) (0081056).

Mnemonic

FREE T

Methodology

Quantitative Electrochemiluminescent Immunoassay
The concentration of free testosterone is derived from a mathematical expression based on the constant for the binding of testosterone to sex hormone binding globulin.

Performed

Sun-Sat

Reported

Within 24 hours

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Collect specimen between 6-10 a.m.

Collect

Serum separator tube or green (lithium heparin).

Specimen Preparation

Separate serum or plasma from cells immediately after collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.6 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

EDTA plasma.

Remarks
Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 1 week; Frozen: 2 months

Reference Interval

Test Number
Components
Reference Interval
  Testosterone, Percentage Free 18 years and older:  1.6-2.9%
0099375 Sex Hormone Binding Globulin
Age Male Female
1-30 days
31-364 days
1-3 years
4-6 years
7-9 years
10-12 years
13-15 years
16-17 years
18-49 years
50 years and older
13-85 nmol/L
70-250 nmol/L
50-180 nmol/L
45-175 nmol/L
28-190 nmol/L
23-160 nmol/L
13-140 nmol/L
10-60 nmol/L
17-56 nmol/L
19-76 nmol/L
14-60 nmol/L
60-215 nmol/L
60-190 nmol/L
55-170 nmol/L
35-170 nmol/L
17-155 nmol/L
11-120 nmol/L
19-145 nmol/L
25-122 nmol/L
17-125 nmol/L
Tanner Stage I
Tanner Stage II
Tanner Stage III
Tanner Stage IV
Tanner Stage V
26-186 nmol/L
22-169 nmol/L
13-104 nmol/L
11-60 nmol/L
11-71 nmol/L
30-173 nmol/L
16-127 nmol/L
12-98 nmol/L
14-151 nmol/L
23-165 nmol/L

0070111 Testosterone, Free (Adult Males or Individuals on Testosterone Hormone Therapy) Male:
14-15 years:  3-138 pg/mL
16-17 years:  38-173 pg/mL
18 years and older: 47-244 pg/mL

Tanner Stage IV:  35-169 pg/mL
Tanner Stage V:  41-239 pg/mL
0070130 Testosterone (Adult Males or Individuals on Testosterone Hormone Therapy) Male:
14-15 years: 33-585 ng/dL
16-17 years: 185-886 ng/dL
18-39 years: 300-1080 ng/dL
40-59 years: 300-890 ng/dL
60 years and older: 300-720 ng/dL

Tanner Stage IV: 165-854 ng/dL
Tanner Stage V: 194-783 ng/dL

Interpretive Data

Free testosterone concentration is calculated using total testosterone (measured by immunoassay) and the binding constant of testosterone and sex hormone-binding globulin (SHBG). Testosterone immunoassays are both imprecise and inaccurate at low testosterone concentrations, such as those found in children and cisgender females. For these individuals, testing by mass spectrometry is recommended; refer to Testosterone, Free and Total, Includes Sex Hormone-Binding Globulin (Adult Females, Children, or Individuals on Testosterone-Suppressing Hormone Therapy) (ARUP test code 0081056).

For individuals on testosterone hormone therapy, refer to cisgender male reference intervals. No reference intervals have been established for males younger than 14 years or for cisgender females. For a complete set of all established reference intervals, refer to ltd.aruplab.com/Tests/Pub/0070109.

Compliance Category

FDA

Note

Hotline History

N/A

CPT Codes

84402; 84403; 84270

Components

Component Test Code* Component Chart Name LOINC
0070113 Testosterone, Free Calculation 2991-8
0070114 Testosterone, Percentage Free 15432-8
0070130 Testosterone by Immunoassay 2986-8
0099375 Sex Hormone Binding Globulin 13967-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Free Testosterone
  • Male testosterone testing
  • SHBG
  • Total Testosterone
Testosterone, Free and Total, Includes Sex Hormone-Binding Globulin (Adult Males or Individuals on Testosterone Hormone Therapy)